Cutting tool using interrupted cut fast tool servo

ABSTRACT

A cutting tool assembly having a tool post capable of lateral movement along a work piece to be cut and an actuator with a tool tip. The actuator provides for control of the movement of the tool tip in an x-direction into and out of the work piece in order to make discontinuous microstructures in it. The machined work piece can be used to make microstructured articles such as films having non-adjacent lenslets.

BACKGROUND

Machining techniques can be used to create a wide variety of work piecessuch as microreplication tools. Microreplication tools are commonly usedfor extrusion processes, injection molding processes, embossingprocesses, casting processes, or the like, to create microreplicatedstructures. The microreplicated structures may comprise optical films,abrasive films, adhesive films, mechanical fasteners having self-matingprofiles, or any molded or extruded parts having microreplicatedfeatures of relatively small dimensions, such as dimensions less thanapproximately 1000 microns.

The microstructures can also be made by various other methods. Forexample, the structure of the master tool can be transferred on othermedia, such as to a belt or web of polymeric material, by a cast andcure process from the master tool to form a production tool; thisproduction tool is then used to make the microreplicated structure.Other methods such as electroforming can be used to copy the mastertool. Another alternate method to make a light directing film is todirectly cut or machine a transparent material to form the appropriatestructures. Other techniques include chemical etching, bead blasting, orother stochastic surface modification techniques.

SUMMARY

A first cutting tool assembly includes a tool post and an actuatorconfigured for attachment to the tool post and for electricalcommunication with a controller. A tool tip attached to the actuator ismounted for movement with respect to a work piece to be cut. Theactuator provides for movement of the tool tip in an x-direction intoand out of the work piece, and the tool tip is in discontinuous contactwith the work piece during cutting of it.

A second cutting tool assembly includes a tool post and an actuatorconfigured for attachment to the tool post and for electricalcommunication with a controller. A tool tip attached to the actuator ismounted for movement with respect to a work piece to be cut. Theactuator provides for movement of the tool tip in an x-direction intoand out of the work piece. The tool tip is in discontinuous contact withthe work piece during cutting, and the assembly can vary a taper-inangle of the tool tip into the work piece and a taper-out angle of thetool tip out of the work piece during the cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated in and constitute a part ofthis specification and, together with the description, explain theadvantages and principles of the invention. In the drawings,

FIG. 1 is a diagram of a cutting tool system for making microstructuresin a work piece;

FIG. 2 is a diagram illustrating a coordinate system for a cutting tool;

FIG. 3 is a diagram of an exemplary PZT stack for use in a cutting tool;

FIG. 4A is a perspective view of a tool tip carrier;

FIG. 4B is a front view of a tool tip carrier for holding a tool tip;

FIG. 4C is a side view of a tool tip carrier;

FIG. 4D is a top view of a tool tip carrier;

FIG. 5A is a perspective view of a tool tip;

FIG. 5B is a front view of a tool tip;

FIG. 5C is a bottom view of a tool tip;

FIG. 5D is a side view of a tool tip;

FIG. 6A is a top sectional view of an interrupted cut FTS actuator;

FIG. 6B is a front sectional view illustrating placement of a PZT stackin an actuator;

FIG. 6C is a front view of an actuator;

FIG. 6D is a back view of an actuator;

FIG. 6E is a top view of an actuator;

FIGS. 6F and 6G are side views of an actuator;

FIG. 6H is a perspective view of an actuator;

FIG. 7A is a diagram illustrating an interrupted cut with substantiallyequal taper-in and taper-out angles into and out of a work piece;

FIG. 7B is a diagram illustrating an interrupted cut with a taper-inangle less than a taper-out angle into and out of a work piece;

FIG. 7C is a diagram illustrating an interrupted cut with a taper-inangle greater than a taper-out angle into and out of a work piece; and

FIG. 8 is a diagram conceptually illustrating microstructures that canbe made using the cutting tool system having an interrupted cut FTSactuator.

DETAILED DESCRIPTION

Cutting Tool System

General diamond turning techniques are described in PCT PublishedApplication WO 00/48037, incorporated herein by reference as if fullyset forth. The apparatus used in methods and for making optical films orother films can include a fast servo tool. As disclosed in WO 00/48037,a fast tool servo (FTS) is a solid state piezoelectric (PZT) device,referred to as a PZT stack, which rapidly adjusts the position of acutting tool attached to the PZT stack. The FTS allows for highlyprecise and high speed movement of the cutting tool in directions withina coordinate system as further described below.

FIG. 1 is a diagram of a cutting tool system 10 for makingmicrostructures in a work piece. Microstructures can include any type,shape, and dimension of structures on, indenting into, or protrudingfrom the surface of an article. For example, microstructures createdusing the actuators and system described in the present specificationcan have a 1000 micron pitch, 100 micron pitch, 1 micron pitch, or evena sub-optical wavelength pitch around 200 nanometers (nm).Alternatively, in other embodiments, the pitch for the microstructurescan be greater than 1000 microns, regardless as to how they are cut.These dimensions are provided for illustrative purposes only, andmicrostructures made using the actuators and system described in thepresent specification can have any dimension within the range capable ofbeing tooled using the system.

System 10 is controlled by a computer 12. Computer 12 has, for example,the following components: a memory 14 storing one or more applications16; a secondary storage 18 providing for non-volatile storage ofinformation; an input device 20 for receiving information or commands; aprocessor 22 for executing applications stored in memory 16 or secondarystorage 18, or received from another source; a display device 24 foroutputting a visual display of information; and an output device 26 foroutputting information in other forms such as speakers for audioinformation or a printer for a hardcopy of information.

The cutting of a work piece 54 is performed by a tool tip 44. Anactuator 38 controls movement of tool tip 44 as work piece 54 is rotatedby a drive unit and encoder 56, such as an electric motor controlled bycomputer 12. In this example, work piece 54 is shown in roll form;however, it can be implemented in planar form. Any machineable materialscould be used; for example, the work piece can be implemented withaluminum, nickel, copper, brass, steel, or plastics (e.g., acrylics).The particular material to be used may depend, for example, upon aparticular desired application such as various films made using themachined work piece. Actuator 38, and the actuators described below, canbe implemented with stainless steel, for example, or other materials.

Actuator 38 is removably connected to a tool post 36, which is in turnlocated on a track 32. The tool post 36 and actuator 38 are configuredon track 32 to move in both an x-direction and a z-direction as shown byarrows 40 and 42. Computer 12 is in electrical connection with tool post36 and actuator 38 via one or more amplifiers 30. When functioning as acontroller, computer 12 controls movement of tool post 36 along track 32and movement of tool tip 44 via actuator 38 for machining work piece 54.If an actuator has multiple PZT stacks, it can use separate amplifiersto independently control each PZT stack for use in independentlycontrolling movement of a tool tip attached to the stacks. Computer 12can make use of a function generator 28 in order to provide waveforms toactuator 38 in order to machine various microstructures in work piece54, as further explained below.

The machining of work piece 54 is accomplished by coordinated movementsof various components. In particular, the system, under control ofcomputer 12, can coordinate and control movement of actuator 38, viamovement of tool post 36, along with movement of the work piece in thec-direction and movement of tool tip 44 in one or more of thex-direction, y-direction, and z-direction, those coordinates beingexplained below. The system typically moves tool post 36 at a constantspeed in the z-direction, although a varying speed may be used. Themovements of tool post 36 and tool tip 44 are typically synchronizedwith the movement of work piece 54 in the c-direction (rotationalmovement as represented by line 53). All of these movements can becontrolled using, for example, numerical control techniques or anumerical controller (NC) implemented in software, firmware, or acombination in computer 12.

The cutting of the work piece can include continuous and discontinuouscutting motion. For a work piece in roll form, the cutting can include ahelix-type cutting (sometimes referred to as thread cutting) orindividual circles around or about the roll. For a work piece in planarform, the cutting can include a spiral-type cutting or individualcircles on or about the work piece. An X-cut can also be used, whichinvolves a nearly straight cutting format where the diamond tool tip cantraverse in and out of the work piece but the overall motion of the toolpost is rectilinear. The cutting can also include a combination of thesetypes of motions.

Work piece 54, after having been machined, can be used to make filmshaving the corresponding microstructures for use in a variety ofapplications. Examples of those films include optical films, frictioncontrol films, and micro-fasteners or other mechanical microstructuredcomponents. The films are typically made using a coating process inwhich a polymeric material in a viscous state is applied to the workpiece, allowed to at least partially cure, and then removed. The filmcomposed of the cured polymer material will have substantially theopposite structures than those in the work piece. For example, anindentation in the work piece results in a protrusion in the resultingfilm. Work piece 54, after having been machined, can also be used tomake other articles having discrete elements or microstructurescorresponding with those in the tool.

Cooling fluid 46 is used to control the temperature of tool post 36 andactuator 38 via lines 48 and 50. A temperature control unit 52 canmaintain a substantially constant temperature of the cooling fluid as itis circulated through tool post 36 and actuator 38. Temperature controlunit 52 can be implemented with any device for providing temperaturecontrol of a fluid. The cooling fluid can be implemented with an oilproduct, for example a low viscosity oil. The temperature control unit52 and reservoir for cooling fluid 46 can include pumps to circulate thefluid through tool post 36 and actuator 38, and they also typicallyinclude a refrigeration system to remove heat from the fluid in order tomaintain it at a substantially constant temperature. Refrigeration andpump systems to circulate and provide temperature control of a fluid areknown in the art. In certain embodiments, the cooling fluid can also beapplied to work piece 54 in order to maintain a substantially constantsurface temperature of the material to be machined in the work piece.

FIG. 2 is a diagram illustrating a coordinate system for a cutting toolsuch as system 10. The coordinate system is shown as movement of a tooltip 62 with respect to a work piece 64. Tool tip 62 may correspond withtool tip 44 and is typically attached to a carrier 60, which is attachedto an actuator. The coordinate system, in this exemplary embodiment,includes an x-direction 66, a y-direction 68, and a z-direction 70. Thex-direction 66 refers to movement in a direction substantiallyperpendicular to work piece 64. The y-direction 68 refers to movement ina direction transversely across work piece 64 such as in a directionsubstantially parallel to a plane of rotation of work piece 64. Thez-direction 70 refers to movement in a direction laterally along workpiece 64 such as in a direction substantially parallel to the axis ofrotation of work piece 64. The rotation of the work piece is referred toas the c-direction, as also shown in FIG. 1. If the work piece isimplemented in planar form, as opposed to roll form, then they-direction and z-direction refer to movement in mutually orthogonaldirections across the work piece in directions substantiallyperpendicular to the x-direction. A planar form work piece can include,for example, a rotating disk or any other configuration of a planarmaterial.

The system 10 can be used for, high precision, high speed machining.This type of machining must account for a variety of parameters, such asthe coordinated speeds of the components and the work piece material. Ittypically must take into consideration the specific energy for a givenvolume of metal to be machined, for example, along with the thermalstability and properties of the work piece material. Cutting parametersrelating to machining are described in the following references, all ofwhich are incorporated herein by reference as if fully set forth:Machining Data Handbook, Library of Congress Catalog Card No. 66-60051,Second Edition (1972); Edward Trent and Paul Wright, Metal Cutting,Fourth Edition, Butterworth-Heinemann, ISBN 0-7506-7069-X (2000); ZhangJin-Hua, Theory and Technique of Precision Cutting, Pergamon Press, ISBN0-08-035891-8(1991); and M. K. Krueger et al., New Technology inMetalworking Fluids and Grinding Wheels Achieves Tenfold Improvement inGrinding Performance, Coolant/Lubricants for Metal Cutting and GrindingConference, Chicago, Ill., U.S.A., Jun. 7, 2000.

PZT Stack, Tool Tip Carrier, and Tool Tip

FIG. 3 is a diagram of an exemplary PZT stack 72 for use in a cuttingtool. A PZT stack is used to provide movement of a tool tip connected toit and operates according to the PZT effect, which is known in the art.According to the PZT effect, an electric field applied to certain typesof materials causes expansion of them along one axis and contractionalong another axis. A PZT stack typically includes a plurality ofmaterials 74, 76, and 78 enclosed within a casing 84 and mounted on abase plate 86. The materials in this exemplary embodiment areimplemented with a ceramic material subject to the PZT effect. Threedisks 74, 76, and 78 are shown for exemplary purposes only and anynumber of disks or other materials, and any type of shapes of them, canbe used based upon, for example, requirements of particular embodiments.A post 88 is adhered to the disks and protrudes from casing 84. Thedisks can be implemented with any PZT material such as for example, abarium titanate, lead zirconate, or lead titanate material mixed,pressed, based, and sintered. One such PZT material is available fromKinetic Ceramics, Inc., 26240 Industrial Blvd., Hayward, Calif. 94545,U.S.A. The disks can also be implemented with a magnetostrictivematerial, for example.

Electrical connections to the disks 74, 76, and 78, as represented bylines 80 and 82, provide electrical fields to them in order to providefor movement of post 88. Due to the PZT effect and based upon the typeof electric field applied, precise and small movement of post 88, suchas movement within several microns, can be accomplished. Also, the endof PZT stack 72 having post 88 can be mounted against one or moreBelleville washers, which provides for preloading of the PZT stack. TheBelleville washers have some flexibility to permit movement of post 88and a tool tip attached to it.

FIGS. 4A-4D are views of an exemplary tool tip carrier 90, which wouldbe mounted to post 88 of the PZT stack for control by an actuator, asexplained below. FIG. 4A is a perspective view of tool tip carrier 90.FIG. 4B is a front view of tool tip carrier 90. FIG. 4C is a side viewof tool tip carrier 90. FIG. 4D is a top view of tool tip carrier 90.

As shown in FIGS. 4A-4D, tool tip carrier 90 includes a planar backsurface 92, a tapered front surface 94, and a protruding surface 98 withangled or tapered sides. An aperture 96 provides for mounting of tooltip carrier 90 onto a post of a PZT stack. Tapered surface 98 would beused for mounting of a tool tip for machining of a work piece. In thisexemplary embodiment, tool tip carrier 90 includes a planar surface toenhance stability of mounting it by providing for more surface areacontact when mounted to a PZT stack, and it includes the tapered frontsurfaces to reduce the mass of it. Tool tip carrier 90 would be mountedto post 88 of the PZT stack by use of an adhesive, brazing, soldering, afastener such as a bolt, or in other ways.

Other configurations of tool tip carriers are possible based, forexample, upon requirements of particular embodiment. The term “tool tipcarrier” is intended to include any type of structure for use in holdinga tool tip for machining a work piece. Tool tip carrier 90 can beimplemented with, for example, one or more of the following materials:sintered carbide, silicon nitride, silicon carbide, steel, titanium,diamond, or synthetic diamond material. The material for tool tipcarrier 90 preferably is stiff and has a low mass.

FIGS. 5A-5D are views of an exemplary tool tip 100, which would besecured to surface 98 of tool tip carrier 90 such as by use of anadhesive, brazing, soldering, or in other ways. FIG. 5A is a perspectiveview of tool tip 100. FIG. 5B is a front view of tool tip 100. FIG. 5Cis a bottom view of tool tip 100. FIG. 5D is a side view of tool tip100. As shown in FIGS. 5A-5D, tool tip 100 includes sides 104, taperedand angled front surfaces 106, and a bottom surface 102 for securing itto surface 98 of tool tip carrier 90. The front portion 105 of tool tip100 is used for machining of a work piece under control of an actuator.Tool tip 90 can be implemented with, for example, a diamond slab.

Interrupted Cut FTS Actuator

An interrupted cut FTS actuator can be used to make smallmicrostructures as the tool tip is in discontinuous contact with workpiece during cutting, creating non-adjacent microstructures. Thesefeatures can be used to make film light guides, micro-fluidicstructures, segmented adhesives, abrasive articles, optical diffusers,high contrast optical screens, light redirecting films, anti-reflectionstructures, light mixing, and decorative films.

The actuator can provide for other advantages. For example, the featurescan be made so small as to be invisible to the naked eye. This type offeature reduces the need for a diffuser sheet to hide the lightextraction features in a liquid crystal display, for example. Use ofcrossed BEF films above the light guide also causes mixing that would incombination with these small features eliminate the need for thediffuser layer. Another advantage is that the extraction features can bemade linear or circular. In the linear case, they can be used withconventional cold cathode fluorescent lamp (CCFL) light sources, forexample. In the circular case, the features can be made on circular arcswith a center point located where an LED would normally be positioned.Yet another advantage relates to programming and structure layout whereall features need not lay along a single line as with a continuousgroove. The area density of the light extraction features can beadjusted deterministically by arranging spacing along the features,spacing orthogonal to the features, and depth. Furthermore, the lightextraction angle can be made preferential by selecting the angle andhalf angles of the cut facets.

The depth of the features may be in the region of 0 to 35 microns, forexample, and more typically 0 to 15 microns. For a roll work piece, thelength of any individual feature is controlled by the revolutions perminute (RPM) of the rotating work piece along the c-axis, and theresponse time of the FTS. The feature length can be controlled from 1 to200 microns, for example. For a helix type cutting, the spacingorthogonal to the grooves (pitch) can also be programmed from 1 to 1000microns. As illustrated below, the tool tip to make the features willtaper-in and taper-out of the material, thereby creating structures, theshape of which are controlled by the RPM, the response time of the FTS,the resolution of the spindle encoder, and the clearance angle of thediamond tool tip (for example, a maximum of 45 degrees). The clearanceangle can include a rake angle of the tool tip. The features can haveany type of three-dimensional shape such as, for example, symmetrical,asymmetrical, semi-hemispherical, prismatic, and semi-ellipsoidal.

FIGS. 6A-6H are views of an exemplary actuator 110 for use inimplementing an interrupted cut microreplication system and process. Theterm “actuator” refers to any type of actuator or other device thatprovides for movement of a tool tip in substantially an x-direction foruse in machining a work piece. FIG. 6A is a top sectional view ofactuator 110. FIG. 6B is a front sectional view illustrating placementof a PZT stack in actuator 110. FIG. 6C is a front view of actuator 110.FIG. 6D is a back view of actuator 110. FIG. 6E is a top view ofactuator 110. FIGS. 6F and 6G are side views of actuator 110. FIG. 6H isa perspective view of actuator 110. Some details of actuator 110 inFIGS. 6C-6H have been removed for clarity.

As shown in FIGS. 6A-6H, actuator 110 includes a main body 112 capableholding an x-direction PZT stack 118. PZT stack 118 is attached to atool tip carrier having a tool tip 136 for using in moving the tool tipin an x-direction as shown by arrow 138. PZT stack 118 can beimplemented with the exemplary PZT stack 72 shown in FIG. 3. The tooltip on a carrier 136 can be implemented with the tool tip carrier shownin FIGS. 4A-4D and the tool tip shown in FIGS. 5A-5D. Main body 112 alsoincludes two apertures 114 and 115 for use in removably mounting it totool post 36, such as via bolts, for machining work piece 54 undercontrol of computer 12.

PZT stack 118 is securely mounted in main body 112 for the stabilityrequired for precise controlled movement of tool tip 136. The diamond ontool tip 136 in this example is an offset 45 degree diamond with avertical facet, although other types of diamonds may be used. Forexample, the tool tip can be V-shaped (symmetric or asymmetric),round-nosed, flat, or a curved facet tool. Since the discontinuous(non-adjacent) features are cut on a diamond turning machine, they canbe linear or circular. Furthermore, since the features are notcontinuous, it is not required that they even be located along a singleline or circle. They can be interspersed with a pseudorandomness.

PZT stack 118 is secured in main body 112 by rails such as rails 120 and122. The PZT stack 118 can preferably be removed from main body 112 bysliding is along the rails and can be secured in place in main body 112by bolts or other fasteners. PZT stack 118 includes electricalconnection 130 for receiving signals from computer 12. The end cap ofPZT stacks 118 includes a port 128 for receiving cooling fluid such asoil from reservoir 46, circulating it around the PZT stack, anddelivering the oil back to reservoir 46, via port 132, for maintainingtemperature control of it. Main body 112 can include appropriatechannels for directing the cooling fluid around PZT stack 118, and thecooling fluid can be circulated by a pump or other device in temperaturecontrol unit 52.

FIG. 6B is a front sectional view illustrating placement of PZT stack118 in main body 112 with the end cap of PZT stack 118 not shown. Mainbody 112 can include a plurality of rails in each aperture for the PZTstacks to hold them securely in place. For example, PZT stack 118 issurrounded by rails 120, 122, 142, and 144 in order to hold it securelyin place when mounted in main body 112. The end cap attached to PZTstack 118 can accommodate bolts or other fasteners to secure PZT stackto one or more of the rails 120, 122, 142, and 144, and the end cap canalso provide for sealing PZT stack 118 in main body 112 for use incirculating the cooling fluid around it. PZT stack 118 can include oneor more Belleville washers positioned between the stacks and the tooltip carrier 136 for preloading of them.

FIGS. 7A-7C illustrate interrupted cut machining of a work piece usingthe exemplary actuator and system described above. In particular, FIGS.7A-7C illustrate use of variable taper-in and taper-out angles of a tooltip, and those angles can be controlled using, for example, theparameters identified above. Each of FIGS. 7A-7C illustrate examples ofthe work piece before and after being cut with varying taper-in andtaper-out angles. The taper-in angle is referred to as λ_(IN) and thetaper-out angle is referred to as λ_(OUT). The terms taper-in angle andtaper-out angle mean, respectively, an angle at which a tool tip entersa work piece and leaves a work piece during machining. The taper-in andtaper-out angles do not necessarily correspond with angles of the tooltip as it moves through a work piece; rather, they refer to the anglesat which the tool tip contacts and leaves the work piece. In FIGS.7A-7C, the tool tips and work pieces can be implemented, for example,with the system and components described above.

FIG. 7A is a diagram illustrating an interrupted cut 150 withsubstantially equal taper-in and taper-out angles into and out of a workpiece 153. As shown in FIG. 7A, a taper-in angle 152 of a tool tip 151into a work piece 153 is substantially equal to a taper-out angle 154(λ_(IN)≈λ_(OUT)). The duration of the tool tip 151 into work piece 153determines a length L (156) of the resulting microstructure. Usingsubstantially equal taper-in and taper-out angles results in asubstantially symmetrical microstructure 158 created by removal ofmaterial from the work piece by the tool tip. This process can berepeated to make additional microstructures, such as microstructure 160,separated by a distance D (162).

FIG. 7B is a diagram illustrating an interrupted cut with a taper-inangle less than a taper-out angle into and out of a work piece 167. Asshown in FIG. 7B, a taper-in angle 166 of a tool tip 165 into a workpiece 167 is less than a taper-out angle 168 (λ_(IN)<λ_(OUT)). The dwelltime of the tool tip 165 in work piece 167 determines a length 170 ofthe resulting microstructure. Using a taper-in angle less than ataper-out angle results in an asymmetrical microstructure, for examplemicrostructure 172, created by removal of material from the work pieceby the tool tip. This process can be repeated to make additionalmicrostructures, such as microstructure 174, separated by a distance176.

FIG. 7C is a diagram illustrating an interrupted cut with a taper-inangle greater than a taper-out angle into and out of a work piece 181.As shown in FIG. 7C, a taper-in angle 180 of a tool tip 179 into a workpiece 181 is greater than a taper-out angle 182 (λ_(IN)>λ_(OUT)). Thedwell time of the tool tip 179 in work piece 181 determines a length 184of the resulting microstructure. Using a taper-in angle greater than ataper-out angle results in an asymmetrical microstructure, for examplemicrostructure 186, created by removal of material from the work pieceby the tool tip. This process can be repeated to make additionalmicrostructures, such as microstructure 188, separated by a distance190.

In FIGS. 7A-7C, the dashed lines for the taper-in and taper-out angles(152, 154, 166, 168, 180, 182) are intended to conceptually illustrateexamples of angles at which a tool tip enters and leaves a work piece.While cutting the work piece, the tool tip can move in any particulartype of path, for example a linear path, a curved path, a path includinga combination of linear and curved motions, or a path defined by aparticular function.

FIG. 8 is a diagram conceptually illustrating microstructures that canbe made using the cutting tool system having an interrupted cut FTSactuator to make a machined work piece and using that work piece to makea structured film. As shown in FIG. 8, an article 200 includes a topsurface 202 and a bottom surface 204. Top surface 202 includesinterrupted cut protruding microstructures such as structures 206, 208,and 210, and those microstructures can be made using the actuators andsystem described above to machine a work piece and then using that workpiece to make a film or article using a coating technique. In thisexample, each microstructure has a length L, the sequentially cutmicrostructures are separated by a distance D, and adjacentmicrostructures are separated by a pitch P. Examples of animplementation of those parameters are provided above.

While the present invention has been described in connection with anexemplary embodiment, it will be understood that many modifications willbe readily apparent to those skilled in the art, and this application isintended to cover any adaptations or variations thereof. For example,various types of materials for the tool post, actuator, and tool tip,and configurations of those components, may be used without departingfrom the scope of the invention. This invention should be limited onlyby the claims and equivalents thereof.

1. A cutting tool assembly, comprising: a tool post; an actuatorconfigured for attachment to the tool post and for electricalcommunication with a controller; and a tool tip attached to the actuatorand mounted for movement with respect to a work piece to be cut, whereinthe actuator provides for movement of the tool tip in an x-directioninto and out of the work piece and wherein the tool tip is indiscontinuous contact with the work piece during cutting of the workpiece.
 2. The cutting tool assembly of claim 1, wherein the actuatorincludes a piezoelectric stack connected to the tool tip, and forelectrical connection with the controller, for controlling the movementof the tool tip.
 3. The cutting tool assembly of claim 1, wherein ataper-in angle of the tool tip into the work piece is substantiallyequal to a taper-out angle of the tool tip out of the work piece duringthe cutting.
 4. The cutting tool assembly of claim 1, wherein a taper-inangle of the tool tip into the work piece is less than a taper-out angleof the tool tip out of the work piece during the cutting.
 5. The cuttingtool assembly of claim 1, wherein a taper-in angle of the tool tip intothe work piece is greater than a taper-out angle of the tool tip out ofthe work piece during the cutting.
 6. The cutting tool assembly of claim1, wherein the actuator includes ports for transmission of a fluidthrough the actuator for cooling of the actuator.
 7. The cutting toolassembly of claim 2, further comprising a washer connected to thepiezoelectric stacks for use in preloading the piezoelectric stack. 8.The cutting tool assembly of claim 1, wherein the tool post isconfigured to move the actuator in the z-direction along the work pieceat a substantially constant speed.
 9. The cutting tool assembly of claim1, wherein the work piece is composed of one of the following materials:aluminum, nickel, copper, brass, steel, or plastic.
 10. A method forcutting a work piece, comprising: providing a tool post; providing anactuator configured for attachment to the tool post and for electricalcommunication with a controller; situating a tool tip in the actuatorfor movement with respect to the work piece to be cut; and configuringthe actuator for the movement of the tool tip in an x-direction into andout of the work piece and providing a signal to the actuator, via thecontroller, such that the tool tip is in discontinuous contact with thework piece during cutting of the work piece.
 11. The method of claim 10,wherein the configuring step includes controlling the movement of thetool tip using a piezoelectric stack.
 12. The method of claim 10,further comprising using a taper-in angle of the tool tip into the workpiece substantially equal to a taper-out angle of the tool tip out ofthe work piece during the cutting.
 13. The method of claim 10, furthercomprising using a taper-in angle of the tool tip into the work pieceless than a taper-out angle of the tool tip out of the work piece duringthe cutting.
 14. The method of claim 10, further comprising using ataper-in angle of the tool tip into the work piece greater than ataper-out angle of the tool tip out of the work piece during thecutting.
 15. The method of claim 10, further including cooling of theactuator using a fluid.
 16. The method of claim 11, further comprisingpreloading the piezoelectric stack using a washer.
 17. The method ofclaim 10, wherein the providing the tool post step includes moving theactuator in the z-direction along the work piece at a substantiallyconstant speed.
 18. The method of claim 10, further comprising rotatingthe work piece during the cutting.
 19. A cutting tool assembly,comprising: a tool post; an actuator configured for attachment to thetool post and for electrical communication with a controller; and a tooltip attached to the actuator and mounted for movement with respect to awork piece to be cut, wherein the actuator provides for movement of thetool tip in an x-direction into and out of the work piece and whereinthe tool tip is in discontinuous contact with the work piece duringcutting of the work piece, wherein the assembly can vary a taper-inangle of the tool tip into the work piece and a taper-out angle of thetool tip out of the work piece during the cutting.
 20. A method formaking a microstructured article, comprising: making a machined workpiece, comprising providing a tool post; providing an actuatorconfigured for attachment to the tool post and for electricalcommunication with a controller; situating a tool tip in the actuatorfor movement with respect to the work piece to be cut; and configuringthe actuator for the movement of the tool tip in an x-direction into andout of the work piece and providing a signal to the actuator, via thecontroller, such that the tool tip is in discontinuous contact with thework piece during cutting of the work piece; applying a viscous materialto the machined work piece such that the material, after the applicationto the work piece, substantially conforms to surface of the machinedwork piece; and removing the material from the machined work piece.